Right now there is no way to query whether BPF programs are
attached to a sockmap or not.
we can use the standard interface in libbpf to query, such as:
bpf_prog_query(mapFd, BPF_SK_SKB_STREAM_PARSER, 0, NULL, ...);
the mapFd is the fd of sockmap.
Signed-off-by: Di Zhu <zhudi2@xxxxxxxxxx>
---
/* v2 */
- John Fastabend <john.fastabend@xxxxxxxxx>
- add selftest code
/* v3 */
- avoid sleeping caused by copy_to_user() in rcu critical zone
---
include/linux/bpf.h | 9 ++
kernel/bpf/syscall.c | 5 ++
net/core/sock_map.c | 88 +++++++++++++++++--
.../selftests/bpf/prog_tests/sockmap_basic.c | 85 ++++++++++++++++++
.../bpf/progs/test_sockmap_progs_query.c | 25 ++++++
5 files changed, 205 insertions(+), 7 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d604c8251d88..db7d0e5115b7 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1961,6 +1961,9 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog);
int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype);
int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value, u64 flags);
+int sockmap_bpf_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr);
+
void sock_map_unhash(struct sock *sk);
void sock_map_close(struct sock *sk, long timeout);
#else
@@ -2014,6 +2017,12 @@ static inline int sock_map_update_elem_sys(struct bpf_map *map, void *key, void
{
return -EOPNOTSUPP;
}
+
+static inline int sockmap_bpf_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_BPF_SYSCALL */
#endif /* CONFIG_NET && CONFIG_BPF_SYSCALL */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4e50c0bfdb7d..17faeff8f85f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3275,6 +3275,11 @@ static int bpf_prog_query(const union bpf_attr *attr,
case BPF_FLOW_DISSECTOR:
case BPF_SK_LOOKUP:
return netns_bpf_prog_query(attr, uattr);
+ case BPF_SK_SKB_STREAM_PARSER:
+ case BPF_SK_SKB_STREAM_VERDICT:
+ case BPF_SK_MSG_VERDICT:
+ case BPF_SK_SKB_VERDICT:
+ return sockmap_bpf_prog_query(attr, uattr);
default:
return -EINVAL;
}
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e252b8ec2b85..ca65ed0004d3 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -1412,38 +1412,50 @@ static struct sk_psock_progs *sock_map_progs(struct bpf_map *map)
return NULL;
}
-static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
- struct bpf_prog *old, u32 which)
+static int sock_map_prog_lookup(struct bpf_map *map, struct bpf_prog **pprog[],
+ u32 which)
{
struct sk_psock_progs *progs = sock_map_progs(map);
- struct bpf_prog **pprog;
if (!progs)
return -EOPNOTSUPP;
switch (which) {
case BPF_SK_MSG_VERDICT:
- pprog = &progs->msg_parser;
+ *pprog = &progs->msg_parser;
break;
#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
case BPF_SK_SKB_STREAM_PARSER:
- pprog = &progs->stream_parser;
+ *pprog = &progs->stream_parser;
break;
#endif
case BPF_SK_SKB_STREAM_VERDICT:
if (progs->skb_verdict)
return -EBUSY;
- pprog = &progs->stream_verdict;
+ *pprog = &progs->stream_verdict;
break;
case BPF_SK_SKB_VERDICT:
if (progs->stream_verdict)
return -EBUSY;
- pprog = &progs->skb_verdict;
+ *pprog = &progs->skb_verdict;
break;
default:
return -EOPNOTSUPP;
}
+ return 0;
+}
+
+static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
+ struct bpf_prog *old, u32 which)
+{
+ struct bpf_prog **pprog;
+ int ret;
+
+ ret = sock_map_prog_lookup(map, &pprog, which);
+ if (ret)
+ return ret;
+
if (old)
return psock_replace_prog(pprog, prog, old);
@@ -1451,6 +1463,68 @@ static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
return 0;
}
+int sockmap_bpf_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+ u32 prog_cnt = 0, flags = 0;
+ u32 ufd = attr->target_fd;
+ struct bpf_prog **pprog;
+ struct bpf_prog *prog;
+ struct bpf_map *map;
+ struct fd f;
+ int ret;
+ u32 id = 0;
+
+ if (attr->query.query_flags)
+ return -EINVAL;
+
+ f = fdget(ufd);
+ map = __bpf_map_get(f);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+
+ rcu_read_lock();
+
+ ret = sock_map_prog_lookup(map, &pprog, attr->query.attach_type);
+ if (ret)
+ goto end;
+
+ prog = *pprog;
+ prog_cnt = (!prog) ? 0 : 1;
+
+ if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+ goto end;
+
+ prog = bpf_prog_inc_not_zero(prog);
+ if (IS_ERR(prog)) {
+ ret = PTR_ERR(prog);
+ goto end;
+ }
+ id = prog->aux->id;
+ bpf_prog_put(prog);
+
+end:
+ rcu_read_unlock();
+
+ if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {
+ ret = -EFAULT;
+ goto err;
+ }
+ if (id != 0 && copy_to_user(prog_ids, &id, sizeof(u32))) {
+ ret = -EFAULT;
+ goto err;
+ }
+ if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+err:
+ fdput(f);
+ return ret;
+}
+
static void sock_map_unlink(struct sock *sk, struct sk_psock_link *link)
{
switch (link->map->map_type) {
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 1352ec104149..23fd89661ef5 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -8,6 +8,7 @@
#include "test_sockmap_update.skel.h"
#include "test_sockmap_invalid_update.skel.h"
#include "test_sockmap_skb_verdict_attach.skel.h"
+#include "test_sockmap_progs_query.skel.h"
#include "bpf_iter_sockmap.skel.h"
#define TCP_REPAIR 19 /* TCP sock is under repair right now */
@@ -315,6 +316,84 @@ static void test_sockmap_skb_verdict_attach(enum bpf_attach_type first,
test_sockmap_skb_verdict_attach__destroy(skel);
}
+static __u32 query_prog_id(int prog)
+{
+ struct bpf_prog_info info = {};
+ __u32 info_len = sizeof(info);
+ int err;
+
+ err = bpf_obj_get_info_by_fd(prog, &info, &info_len);
+ if (CHECK_FAIL(err || info_len != sizeof(info))) {
+ perror("bpf_obj_get_info_by_fd");
+ return 0;
+ }
+
+ return info.id;
+}
+
+static void test_sockmap_progs_query(enum bpf_attach_type attach_type)
+{
+ struct test_sockmap_progs_query *skel;
+ int err, map, verdict, duration = 0;
+ __u32 attach_flags = 0;
+ __u32 prog_ids[3] = {};
+ __u32 prog_cnt = 3;
+
+ skel = test_sockmap_progs_query__open_and_load();
+ if (CHECK_FAIL(!skel)) {
+ perror("test_sockmap_progs_query__open_and_load");
+ return;
+ }
+
+ map = bpf_map__fd(skel->maps.sock_map);
+
+ if (attach_type == BPF_SK_MSG_VERDICT)
+ verdict = bpf_program__fd(skel->progs.prog_skmsg_verdict);
+ else
+ verdict = bpf_program__fd(skel->progs.prog_skb_verdict);
+
+ err = bpf_prog_query(map, attach_type, 0 /* query flags */,
+ &attach_flags, prog_ids, &prog_cnt);
+ if (CHECK(err, "bpf_prog_query", "failed\n"))
+ goto out;
+
+ if (CHECK(attach_flags != 0, "bpf_prog_query",
+ "wrong attach_flags on query: %u", attach_flags))
+ goto out;
+
+ if (CHECK(prog_cnt != 0, "bpf_prog_query",
+ "wrong program count on query: %u", prog_cnt))
+ goto out;
+
+ err = bpf_prog_attach(verdict, map, attach_type, 0);
+ if (CHECK(err, "bpf_prog_attach", "failed\n"))
+ goto out;
+
+ prog_cnt = 1;
+ err = bpf_prog_query(map, attach_type, 0 /* query flags */,
+ &attach_flags, prog_ids, &prog_cnt);
+ if (CHECK(err, "bpf_prog_query", "failed\n"))
+ goto detach;
+
+ if (CHECK(attach_flags != 0, "bpf_prog_query",
+ "wrong attach_flags on query: %u", attach_flags))
+ goto detach;
+
+ if (CHECK(prog_cnt != 1, "bpf_prog_query",
+ "wrong program count on query: %u", prog_cnt))
+ goto detach;
+
+ if (CHECK(prog_ids[0] != query_prog_id(verdict), "bpf_prog_query",
+ "wrong prog id on query: %u", prog_ids[0]))
+ goto detach;
+
+detach:
+ bpf_prog_detach2(verdict, map, attach_type);
+out:
+ test_sockmap_progs_query__destroy(skel);
+
+}
+
void test_sockmap_basic(void)
{
if (test__start_subtest("sockmap create_update_free"))
@@ -341,4 +420,10 @@ void test_sockmap_basic(void)
test_sockmap_skb_verdict_attach(BPF_SK_SKB_STREAM_VERDICT,
BPF_SK_SKB_VERDICT);
}
+ if (test__start_subtest("sockmap progs query")) {
+ test_sockmap_progs_query(BPF_SK_MSG_VERDICT);
+ test_sockmap_progs_query(BPF_SK_SKB_STREAM_PARSER);
+ test_sockmap_progs_query(BPF_SK_SKB_STREAM_VERDICT);
+ test_sockmap_progs_query(BPF_SK_SKB_VERDICT);
+ }
}
diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c b/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
new file mode 100644
index 000000000000..ec0da297cf80
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_SOCKMAP);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u64);
+} sock_map SEC(".maps");
+
+SEC("sk_skb")
+int prog_skb_verdict(struct __sk_buff *skb)
+{
+ return SK_PASS;
+}
+
+SEC("sk_msg")
+int prog_skmsg_verdict(struct sk_msg_md *msg)
+{
+ return SK_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
+
--
2.27.0
